1. Field of the Invention:
This invention relates to vinyl chloride homopolymer and vinyl chloride copolymer foam compositions prepared by frothing. These compositions contain silicone surfactant frothing agents and oleophilic frothing aids.
2. Description of the Prior Art:
Techniques for the preparation of vinyl chloride homopolymer and vinyl chloride copolymer foam compositions from plastisols are well known in the polymer art. Also the literature on polyvinylchloride and actate modified polyvinylchloride resin plastisol preparation is quite extensive. Reference may be made to the following publications:
Boehm and Dietz, "Vinyl Froth Foams Via the Oakes Continuous Mixer," Diamond Shamrock Chemical Company Technical Service Information Report No. 3-71, Apr. 30, 1971. PA0 Boehm and Dietz, "The `Ulok` PVC Carpet Backing System," Diamond Shamrock Chemical Company Technical Service Information Report No. 4-71, May 5, 1971. PA0 Simoneau, "Silicone Surfactants in Mechanically Frothed Vinyl Plastisol Foams," Rubber World, p. 49, August, 1970. PA0 Renshaw and Garlick, "How to Back Carpets with PVC," SPE Journal, Vol. 28, p. 21 (1972). PA0 Keil and Webb, "Mechnically Frothed Vinyl Plastisol Foams," Journal of Cellular Plastics, Vol. 6, No. 4, p. 3, July/August, 1970. PA0 "Lubricant Additives" by Dr. M. W. Ranney. Published by Noyes Data Corp., Park Ridge, N. J. 1973. PA0 "gear and Transmission Lubricants" by C. J. Boner. Published by Reinhold Publishing Corp. 1964. PA0 "Lubricant Additives" by. C. V. Smalheer and R. Kennedy Smith. Published by Lezius-Hiles Co., Cleveland, Ohio 1967. PA0 "Lubrication and Lubricants" by Eric R. Braithwaite. Published by Elsevier Publishing Co. 1967. PA0 "Manufacture of a Highly Basic Engine Oil Detergent Additive" American Chemical Society, Division of Petroleum Chemistry - General
Polyvinylchloride (PVC) foam for use as carpet and rug backing and in other markets has certain inherent advantages over other foamed polymers. PVC foams for rug and carpet backing have high tensile and tear strengths; they are more resistant to scuffing, and they have stronger tuff-lock. Also, of significant importance, PVC foams are more fire retardant than other foam polymers.
There are three general methods for producing foam from plastisols . . . compressed gas, chemical blowing agents, and frothing (mechanical whipping). In the frothing method, the most widely used method for producing fine open cell foam, PVC foam is produced by mechanical whipping of the plastisol to incorporate air into the plastisol and then fusing the foam at a relatively low temperature of about 270.degree. to about 290.degree.F. About the only disadvantage of this relatively simple frothing method is the high cost of the silicone surfactant frothing agent.
Additional information on preparation of PVC foam compositions by frothing may be found in U.S. Pat. No. 3,511,788 - Keil - issued May 12, 1970 and U.S. Pat. No. 3,814,706 - Simoneau et al issued June 4, 1974. These patents described preparation of froths using silicone surfactant frothing agents and use of these froths in various applications including the coating of substrates such as rugs and carpets. The teachings of these patents as they apply to the preparation of froths and their use are incorporated by reference herein.